Patent CA-1313686-C (CA)
Title: Load dependent valve for railway vehicles
Inventor: TAMAMORI HIDEO
IPC: B60T15/36
Filed: 1988-12-28
Granted: 1993-02-16
Abstract: (Case No. 8508) ABSTRACT OF THE DISCLOSURE A  load  dependent  valve for railway cars comprising, a first  spring having one end contacting a balance piston and having  the  other  end supported by a first spring retainer which  extends  through  center part of a control piston.  A second  spring  having one end contacting the balance piston side  and  having the other end supported by a second spring retainer,   a  first  spring  adjusting  mechanism  disposed between  the  first spring retainer and the side of the main valve  body for adjusting the compressive force of the first spring.    A  second  spring  adjusting  mechanism  disposed between  the  second spring retainer and side of the control piston  for  adjusting  the  compressive force of the second spring.    An  air  supply chamber connected to a compressed air  source.  An output chamber connected to an output port, an  exhaust  chamber which opens to the atmosphere.  A valve seat  deposed  in  an  air supply passage which is connected between  the  air  supply  chamber and the output chamber on the  adjacent side of the air supply chamber.  An air supply valve  is  biased  to  seat  on  the valve seat.  An exhaust valve  rod  having  a  valve  tip which faces the air supply valve  and  which  fits  the  air  supply passage and has an exhaust  air  bore,  one end of which opens at the valve tip and  the other end of which opens at the exhaust chamber.  A control  piston  including a control piston diaphragm having an  inner  edge  which  is  fixed to the main valve body and having  an  outer  edge which is fixed to the control piston main  body, and which generates a force to move the exhaust valve  rod  in the direction of the air supply valve when it receives   a   control  air  pressure.    A  balance  piston including  a  balance  piston diaphragm having an inner edge which  is  fixed  to the main valve body and having an outer edge  which  is  fixed  to  the balance piston main body and which  receives  the  air  pressure from the output chamber, and  generates  the  balance  force  against  the  force.  A middle  body  member  forming  the  air  supply chamber, air supply  passage,  valve  seat,  and the air supply valve.  A position  adjusting  mechanism  by  which  the  middle  body member  can  be  moved  in  the direction of movement of the exhaust  valve  rod and also which can be fixed in the moved position.   A plurality of first fins which are fixed around the  piston  main  body  on  the low pressure side along the direction   of  movement  facing  its  upper  edges  to  the diaphragm  of  the  same  piston, while the side opposite to that  receiving  the  air pressure of at least one piston of the  two pistons is set at a pressure lower than the minimum value  of  the  air  pressure.    A plurality of second fins which  are  located  in  the  main  valve body and which are placed  between  the  first  fins,  and  in  which the first surface  which connects the upper edges of the first fins on the  side  of  the  diaphragm  intersects  with  the  second surface  which  connects  the upper edges of the second fins on the side of the diaphragm.